Method and apparatus for creating an adaptive mosaic pixel-wise virtual Bayer pattern

ABSTRACT

A method and apparatus for creating an adaptive mosaic pixel-wise virtual Bayer pattern. The method may include receiving a plurality of monochromatic images from an array of imaging elements, creating a reference ordered set at infinity from the plurality of monochromatic images, running a demosaicing process on the reference ordered set, and creating a color image from the demosaiced ordered set. One or more offset artifacts resulting from the demosaicing process may be computed at a distance other than infinity, the ordered set may be modified in accordance with the computed offsets.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/045,774 filed Oct. 3, 2013 to El Dokor et al., titled “Method andApparatus for Generating Depth Map from Monochrome Microlens and ImagerArray, which in turn claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/711,177, filed Oct. 8, 2012, to Hauptman et al.,titled “Multi-zoom Functionality on a Mobile Device”, the contents ofthese applications being incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates generally to a depth perception based Bayerpattern that is derived from a plurality of monochromatic portions of animage sensor, and more particularly to an adaptive Bayer pattern thatpreferably changes its configuration, depending on depth perception inthe field of view. One or more reference Bayer patterns are preferablygenerated, and an adaptive demosaicing scheme may be computed from theBayer pattern as part of an image processing pipeline.

BACKGROUND OF THE INVENTION

Camera lens arrays have become more popular with the introduction ofsuch designs by Pelican Imaging and as used in the Lytro camera.Approaches exploiting camera and lens arrays mostly deal with developingsuper resolution techniques that try to discern more accurate, higherresolution images from lower resolution, mostly color-sensitive images.But none of these approaches provide a novel way for discerning depthfrom such a camera lens array that is power-efficient and cost-friendly.

Therefore, it would be beneficial to provide an improved approach thatovercomes the drawbacks of the prior art.

SUMMARY OF THE INVENTION

In accordance with one or more embodiments of the present invention, asis shown in FIG. 1, a sensor array including sensor elements for RGB(Red, Green 1, Green2, Blue) is shown. FIG. 2 depicts two differentmicrolens/sensor array example formats, each circular element 210preferably comprising a sensor array as shown in FIG. 1. FIG. 2a showsan array including a total of 4 such sensors in a 2×2 format, while FIG.2b shows a more complex sensor array, effectively comprising 16 versionsof the sensor shown in FIG. 1 in a 4×4 format. While the arraysdescribed herein and throughout the application are preferably amicrolens array, any array of cameras, lenses or the like may beemployed, as long as providing relative position changes between thevarious elements of the sensor array configuration.

In accordance with one or more embodiments of the invention, a SyntheticBayer pattern is preferably produced from a series of observations bycombining all of the different observations into a new set—a novelmethod in which the Bayer pattern is synthetically reconfigured,per-pixel to generate a color image.

In accordance with the various embodiments of the present invention,given a set of monochromatic images representing the set of primarycolor Low Resolution (LR) images, the inventive solution strives torearrange the set of LR pixel elements belonging to each LR image, sothat a mosaic pixel-element pattern can be generated correspondingone-to-one to each element from the LR elements. This is very differentfrom various well known super resolution techniques (as will bedescribed in greater detail below) in that the various embodiments ofthe present invention do not strive to look for a High Definition (HD)grid. Instead of employing such an HD grid, embodiments of the presentinvention define a virtual color image that can be constructed bydemosaicing a Bayer pattern that can be extracted from some arrangementof the pixel elements, and knowing that such an arrangement iscontingent upon correctly matching the various light-sensitive pixelelements. The inventive approach further assumes that there is no fixedpixel-wise element set that can be used across all frames. Rather, apixel-wise arrangement referred to as an adaptive, or synthetic, Bayerpattern, will change nearly every frame.

In accordance with one or more embodiments of the present invention, theinventors of the present invention have recognized that smartphonestypically come standard with a front-facing camera as well as aback-facing camera. The inventors of the present invention havetherefore determined that when a user is viewing data from theback-facing camera, it may be useful to employ the front-facing camerato extract critical information from the field-of-view and produce atouchless device that establishes a gestural interface.

In accordance with the various embodiments of the present invention adual-pair of front-facing cameras may be employed. One camera may be ata higher resolution than the other camera. For instance, one camera maybe at 1080p, while the second camera may have VGA resolution. See FIGS.1 and 2 for an illustration of a front-facing dual sensor device. Thus,providing multiple front facing sensors may be employed.

Still other objects and advantages of the invention will in part beobvious and will in part be apparent from the specification anddrawings.

The invention accordingly comprises the several steps and the relationof one or more of such steps with respect to each of the others, and theapparatus embodying features of construction, combinations of elementsand arrangement of parts that are adapted to affect such steps, all asexemplified in the following detailed disclosure, and the scope of theinvention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

This patent or application file contains at least one drawing executedin color. Copies of this patent or patent application publication withcolor drawing(s) will be provided by the Office upon request and paymentof the necessary fee.

For a more complete understanding of the invention, reference is made tothe following description and accompanying drawings, in which:

FIG. 1 depicts a sensor;

FIGS. 2(a) and 2(b) depict alternative configurations of a sensor arrayto be employed in accordance with one or more embodiments of the presentinvention;

FIG. 3 is a flowchart diagram depicting an adaptive demosaicingprocessing accordance with an embodiment of the invention;

FIG. 4 is a flowchart diagram depicting an overall method in accordancewith an embodiment of the invention;

FIG. 5 depicts a reference image generated at an infinity distance froman object in accordance with an embodiment of the invention;

FIG. 6 depicts monochromatic artifacts of an object at less than aninfinity distance in accordance with an embodiment of the invention;

FIG. 7 further depicts additional monochromatic artifacts of an objectat less than an infinity distance in accordance with an embodiment ofthe invention;

FIG. 8 depicts an initial RGB image with monochrome-encoded alignmentoffsets in accordance with an embodiment of the invention;

FIG. 9 depicts corresponding segmented ghosting artifacts/offsets due tomisalignment in accordance with an embodiment of the invention;

FIG. 10 illustrates the overlap between images generated from pixel-wisesynthetic Bayer patterns at infinity and at a second ordered set from adifferent set of disparity offsets in accordance with an embodiment ofthe invention;

FIG. 11 depicts an example of shifting pixels along the diagonals of animage in accordance with an embodiment of the invention;

FIG. 12 depicts a clear and IR sensor presented in accordance with anembodiment of the invention;

FIG. 13 depicts a flowchart diagram highlighting the extraction of anSR-based image from a set of LR observations, including that of apanchromatic LR sensor, in accordance with an embodiment of theinvention;

FIG. 14 depicts three frames of low resolution data, offset from eachother on a higher resolution grid in accordance with existing superresolution techniques;

FIG. 15 depicts an ordered set of data on the high resolution grid inaccordance with image restoration;

FIG. 16 depicts a picture snapping functionality provided in accordancewith n embodiment of the invention;

FIG. 17 depicts a picture taking functionality for taking groupportraits by gesturing a thumbs-up to the camera while in the field ofview on accordance with an embodiment of the invention;

FIG. 18 depicts a scenario in which a smartphone acts as the maincompute device for detecting gesture recognition in accordance with asmart TV environment in accordance with an embodiment of the invention;and

FIG. 19 depicts a watch for use with the various embodiments of theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

One or more embodiments of the invention will now be described, makingreference to the following drawings in which like reference numbersindicate like structure between the drawings.

The inventors of the present invention have determined that usingimaging data from the noted image sensor arrays of FIG. 2 (the variousembodiments of the invention will be described making use of the 2×2array of FIG. 2(a), although the concepts of the invention areapplicable to any array configuration), parallax provided by thelocations of the different sensor elements of the array may be exploitedto generate depth information. Thus as noted above and as is furthershown in FIG. 3, by employing monochrome images 310 from each of thesensor array positions, overlaying of these images provides parallaxinformation indicative of depth information of the scene. Through theperformance of segmentation and disparity decomposition at step 320,temporal stability feature extraction at step 330, and adaptivedemosaicing at step 340, a final image 350 may be provided. Thus, thedetermined depth information may be employed to generate an adaptivedemosaicing scheme. The inventors of the present invention havedetermined the following:

1. If one looks from far enough away in a field-of-view of an arraycamera or of a microlens array sensor such as the one described inaccordance with the various embodiments of this invention, then all ofthe pixel elements from any of the sensor arrays will view the samescene. In other words, at infinity, all the pixel-element data from thevarious sensors subtend the same set of locations in the scene. Thisallows some practical conclusions that define an infinity distance, andthat allow for setting up a reference frame for use in determiningparallax and depth information in a scene.

2. Providing a set of data that is subdivided into four monochromaticimages also helps reduce cross talk between the channels and providescleaner pixels.

3. While there have been many super resolution approaches to resolvingthe problem of depth as well as the convergence of a Bayer pattern withdepth to produce an acceptable demosaicing result, most of theapproaches dramatically lower resolution of the final data set, i.e.relative the total number of starting pixels, and are computationallyvery taxing.

4. If a Bayer subimage pattern is used for generation of monochromesubimages, then an ordered set of pixels can be generated to representthe background image, by transforming the Bayer pattern into an orderedset at the pixel level of interest.

5. Defining a set of four monochromatic images, comprised of primarycolors, like, for instance two green, one blue and one red, creates thatordered set that will be used as a composite pixel-level Bayer patternin accordance with the various embodiments of the invention.

6. Lining up the green images for disparity offsets effectively helps inlining up the red and blue images as well, since they are epipolar withone of the two existing images.

7. If one starts looking at objects that are a located a little closerto the sensor as compared to the infinity distance produced image, thedemosaicing process produces artifacts that are apparent and easy toextract.

8. Re-aligning the pixel-wise synthetic Bayer pattern can help get ridof such artifacts and aid in producing a crisp image.

9. One can then define a new ordered set that varies row-wise, andcolumn-wise, comprised of subsets of the four monochromatic images.

10. If one follows these observations, then one is in no need of ahigh-resolution coordinate grid, as defined in prevalent SR and imagerestoration techniques. In fact, such a grid becomes cumbersome to buildand maintain.

The various embodiments of the present invention also present gesturefunctionality with a mobile device using such a camera or a pair offront-facing cameras. The device can be a smartphone or a tablet. Theuser is able to use gestures to enable the device with multiple zoomfunctionality. As an example, in a camera application, the user is ableto use a three-dimensional pinch gesture to zoom, or a thumbs-up gestureto snap a picture. A number of applications are presented in this workas well as illustrations for such applications. Novel three-dimensionaleye tracking with multiple degrees of freedom is also proposed.

Therefore, in accordance with the elements determined by the inventorsof the present invention noted above, a method and system for generatingone or more adaptive Bayer patterns from one or more monochrome imagesis provided.

Given a set of monochromatic images that are light sensitive todifferent components of the wavelength, a well-ordered set ofpixel-element patterns that minimizes the error between the currentconstructed set, and another set generated while viewing the scenethrough the same complex sensor pattern at infinity is generated inaccordance with one or more embodiments of the present invention.Specifically, one can generate a set of patterns that mitigate thaterror, and if so, use this information to determine depth information tobe employed in an adaptive demosaicing process. In order to employ theinventive system and method, one must first construct a reference image.As noted above, for construction of the reference image, as well asduring later use of the system to generate depth information, fourdifferent images are preferably obtained from a micro lens (or othercamera) array.

Referring next to FIG. 4, a flowchart depicting an overall method inaccordance with an embodiment of the invention is shown. One or more ofthe steps shown in FIG. 4 may be omitted or reordered as desired inaccordance with alternative embodiments of the invention. As is shown inFIG. 4, an inventive new pixel-based synthetic Bayer pattern isgenerated from a set of four monochromatic images. This synthetic Bayerpattern has a resolution that is approximately the resolution of theoriginal sensor, after adding up all of the pixel elements. As is shownin FIG. 4, an initial image at infinity is first generated, by settingup a pixel-wise ordered set from all four light-sensitive images,assumed to be at infinity. In step 410, a plurality of monochromeimages, generated from data received by each of a plurality of sensorelements in a sensor array (as described above) are aligned. An orderedset of images is then created at infinity in step 420. This infinityimage is then defined as the reference image in step 430. Demosaicing isthen performed on the ordered set at infinity in step 440. Note that theghosting artifacts will exist on the data. In spite of the artifacts,salient scene information can still be extracted from the ordered set,and thus offsets are computed between the monochromatic images fromartifacts in step 450. For instance, one such type of information mayinclude skin pixels. Because of the artifacts, not all of the skinpixels can be extracted at one time, however, one can extract asignificant number of them, enough to localize the rest of the steps inthe process to a region or regions in the field-of-view.

This step is then followed by the process of modifying the ordered setto adapt to the computed offsets in step 460, and is achieved bysegmentation/disparity decomposition, in which regions in each of themonochrome images are first segmented, and then their disparities arecomputed. Temporal stability analysis as well as other salient featuresextraction is then attempted. Once the disparity that is associated withevery pixel in the scene is known, one can then modify the initialinfinity-based ordered set to produce a new demosaiced ordered set atstep 470, based on the disparity computation. This new ordered set willthen constitute a final version of the image for that particular frame.The whole process is then attempted again for each frame at step 480.This is desirable, since objects move in the field-of-view, and hence,it is important to take that aspect into account in an adaptivedemosaicing Bayer pattern.

Details of each of the steps noted above in FIG. 4 will now be describedin greater detail.

Generating the Reference Image

As noted with reference to FIG. 4, an ordered set of data is obtainedfrom the images generated from the sensor array, in this case fourimages, such that an initial Bayer pattern is obtained. After performingsteps 410, 420 and 430 in FIG. 3, this Bayer pattern is then used todemosaic the ordered set at infinity in step 440 producing R, G, and Bcolors. For instance, if one is presented with a 2×2 set ofmonochromatic images from a microlens array, then one can represent theimage at infinity as:I _(∞)(x,y,∞)={I _(R)(x,y),I _(g) _(r) (x+1,y),I _(B)(x,y+1),I _(g) _(b)(x+1,y)}

Once this ordered set is generated then demosaicing can be computed andthe individual R, G, and B channel images may then be generated.

Consider then, this generated image at infinity, an example of which isdepicted in FIG. 5, as the reference image. It is an image in which allof the datasets are lined up near perfectly at infinity, and the orderedset generates a perfectly aligned image at that depth. Note thatinfinity may be a few inches or a few kilometers, depending on the imagecapture apparatus, scene, colors, optics, etc. The assumption forreaching infinity is that one can generate an ordered set thatrepresents a reference image from four neighboring images can then holdtrue, and can be used.

In a way, this reference background image is one of a set of imageswhose dimensions approximately equate to that of the four images, puttogether, i.e. 4× the original dimensions. This image also representsthe point beyond which all images look fairly identical to each other,once demosaicing takes place after sufficient white balancing betweenthe different images. One is then able to generate an ordered set atinfinity; more importantly, one has the ability to use this image as areference image, since it represents the ordered set at infinity, henceevery other image taken at other than infinity will have componentsoffset from it. Once demosaicing is performed on the infinity-orderedset, every other image that is generated at other than infinityhenceforth will have depth-related artifacts resulting from anysubsequent demosaicing processes that take place.

Identifying Depth from Demosaicing Artifacts

If a reference image, I, is well-ordered and clearly generated in RGB atinfinity, as shown in FIG. 5, then the assumption holds that it wouldhave various artifacts at almost any other depth that is discernable,since the monochrome images generating the RGB image would not line upwith each other as correctly at any other depth. In accordance with thevarious embodiments of the present invention, the farther the depthvalue is from the background image, i.e. the closer an object or partsof an image are to the imager, the greater the number of artifacts thatcan be interpreted into discernible disparity, and hence, depth,information.

Defining a “Discernible” Depth

In accordance with the one or more embodiments of the invention, theinventors have determined that an artifact is generated when objectboundaries don't line up between two or more of the four componentimages when these images are taken at a depth other than infinity. Forinstance, referring next to FIGS. 6 and 7, a background image is firstgenerated from an ordered set (see FIG. 5 above), and then it isobserved what happens when one brings a subject's hand closer to theimaging apparatus in the field-of-view. As is shown in FIG. 6, one ormore monochromatic green artifacts 610 are shown around the fingers onthe left-hand side, while one or more monochromatic red artifacts 620are shown on the right-hand side. In FIG. 7, similar artifacts 710 canbe seen. FIG. 8 additionally depicts an initial RGB image withmonochrome-encoded alignment offsets 810, 820 and 830. FIG. 9 depictscorresponding segmented ghosting artifacts/offsets 910, 920 and 930 alsodue to misalignment. The determination of such misalignment, and thus adiscernible depth, may take place in real time. Such real timeprocessing to determine these artifacts need only be performed onchanges in an image from the prior image. Thus, in accordance with anembodiment of the invention, misalignment artifacts are preferably onlycomputed from regions or pixels in the image that have changed since theprior image. The rest of the image can be synthetically carried over andneed not be searched for such misalignment artifacts.

FIG. 10 illustrates the overlap between images generated from pixel-wisesynthetic Bayer patterns at infinity and at a second ordered set from adifferent set of disparity offsets. As is shown in FIG. 10, a region1010 represents a section of a difference image that is common betweenthe two common component images (i.e. in FIGS. 6-9, the non-ghosted orartifact portion of the image). Regions 1020 therefore represent thenon-overlapping portions of the component images (i.e. the artifacts inFIGS. 6-9). Thus, as is shown, some of the regions overlap, while othersdon't.

Such artifacts inherently point to depth discontinuities, as well asmisalignments between the various monochrome images during demosaicing.By measuring the magnitude of the misalignment, in accordance with thevarious embodiments of the invention, it is possible to measuredisparity between the reference image and another image generated frommonochromatic images taken at a depth other than at infinity. Themonochromatic, green, lining for instance around the fingers visuallyencodes depth, making it discernable, and relatively easy to extract,and hence also easy to extract depth information therefrom.

Since this image represents the set of a perfectly aligned Bayerpattern, it can be used to extract a perfectly demosaiced image with thethree primary color channels.

Encoded Artifacts from Depth-Misaligned Image Sets

As objects present in images taken at a depth other than infinityviolate the infinity reference image, and its associated criteria, a newset is preferably used, comprised of modified, row-wise pixel offsets,to adjust the demosaicing algorithm. These artifacts have certainadvantages, allowing for the further features of the present inventionto be utilized:

1. As noted above with respect to FIGS. 5 and 6, these artifacts appearas translucent ghost artifacts or sets of ghost artifacts around theboundaries and discontinuities of various objects.

2. These artifacts are clearly delineated, and can easily be extracted,since they characteristically are comprised of monochromatic coloroffsets.

3. The width and height of these artifacts indicate disparity values inthe horizontal and vertical directions respectively.

4. Building on this last point, being able to discern depth in multipledimensions is another advantage of this lens configuration.

However, the main difference between prior art super resolutiontechniques in existence and the embodiments of the present invention isthat the present invention does not strive to “fill in the blanks” ofmissing data. Instead, it is assumed that there exists a set oflocations for every (x,y) value in the image, as will be described belowin greater detail.

Adaptive Demosaicing and Generation of a Synthetic Bayer Pattern

The process for adaptive demosaicing will now be described in greaterdepth, in accordance with the various embodiments of the presentinvention. Given four

$\left( {\frac{n}{2} \times \frac{m}{2}} \right)$monochromatic source images, an l₁×l₂ set of images can be generatedwith a resolution of approximately (n×m, approximately four-times theresolution of the original set of images. Where l₁ represents the totalset of horizontal disparity images, and l₂ represents the total set ofvertical disparity images. A total of approximately (l₁×l₂×n) pixels isgenerated.

This is accomplished by first creating a single n×m ordered set atinfinity, as described above with respect to FIG. 4, and then aligningin both the vertical and horizontal dimensions. To successfully keep theimages aligned, producing crisp demosaicing, depth estimation ispreferably constantly undertaken in tandem with demosaicing.

Consider the set, S representing the entire set of demosaiced imagesproduced at various depths. One can represent S as the union of all ofthese candidate images' pixels, such that:S={I _(R1,R2)(x,y)∪I _(1,R2)(x,y) . . . ∪I _(l) ₁ _(,R2)(x,y) . . . ∪I_(R1,1)(x,y)∪I _(R1,2)(x,y) . . . ∪I _(R1,l) ₂ (x,y)}

Visualizing the Set, S

By combining horizontal and vertical displacements, one can see howcombinations of shifts within an image can create intermediate versionsof the images presented above, by aligning the various disparitiesacross all four images. However, all of these images are presented inthe set above. Provided the images are aligned row-wise, one canvisualize S in three dimensions, such that multiple pixels occupy thesame location, by corresponding to different shifts in the monochromaticsensors.

Note on the Inventive Demosaicing Process

S comprises a bounded set (Gaughan, 1997). Hence, the search space fordemosaicing is also bounded, limited by the total number of pixels thatone or a combination of the monochromatic images can be shifted by. Inaccordance with one or more embodiments of the invention, first definethe set of monochromatic images M whose dimensions are

$\left( {\frac{n}{2} \times \frac{m}{2}} \right).$Then define a candidate demosaiced image I, such that:

IεS, the set of all possible demosaiced images.

The candidate demosaicing scheme can belong to one of the imagespresented above, or a combination of these images.

So, the set of all demosaiced images is known and hence, the set ofsolutions to the problem of demosaicing.

Computation of the Difference Image Through Disparity Decomposition

Taking advantage of both CPU and GPU computation capabilities that areavailable on both the CPU and the GPU of a computer or mobile device(although any appropriate processor available may be employed, one cangenerate disparity decomposition in a manner similar to that describedin U.S. patent application Ser. Nos. 12/784,123; 12/784,022; 13/025,038;13/025,055; 13/025,070; 13/297,029; 13/297,144; 13/294,481; and Ser. No.13/316,606, the entire contents of each of these application beingincorporated herein by reference. Note that disparity decomposition maybe performed along the vertical, horizontal, or diagonal directions, aswell as any combinations of such directions. The invention alsocontemplates an alternative approach in which image data is first maskedfor skin tone providing an initial demosaiced image, and then runthrough disparity decomposition on the masked images.

Note that in accordance with the invention, it is possible to shiftalong any direction. So, using the shift along the diagonal allowstaking advantage of two LR imagers that are sensitive to the same lightcolor. For instance, one can shift along the diagonals for two greenimages, thus providing an additional means of computing depth from twoidentical channels. An example of shifting along the diagonals ispresented in FIG. 11

Putting it all Together—Adaptive Real-Time Demosaicing

A new form of demosaicing is then defined in accordance with the variousembodiments of the invention, one which adaptively changes a virtual (orsynthetic) pixel-wise Bayer pattern that is constantly changing. Byrealigning depth per-pixel, an updated well-aligned image is alwaysgenerated that addresses the demosaicing artifacts that are associatedwith pixel-wise sets as defined in the work.

Operation Under Low Lighting Conditions

The concept of a synthetic Bayer pattern can be extended to theoperation of the system under low lighting conditions. This can beaccomplished by either interleaving a clear or an IR version sensor, orboth, with the monochromatic LR sensors. Such an embodiment of theinvention is presented in FIG. 12, depicting such a clear and IR sensor,but either one or the other may be exclusively employed.

The standard demosaicing approach can be modified to add a scale factor,based on the response of the pixel-level elements from the clear or IRversion. So, the pixel-wise element set, described earlier, can berewritten as:I _(∞)(x,y,∞)={I _(R)(x,y),I _(g) _(r) (x+1,y),I _(B)(x,y+1),I _(g) _(b)(x+1,y),I _(C)(x+1,y)}

where I_(C) represents the contribution from the clear channel image.Note that one of the other channels can be replaced by a clear channelor an IR channel. This is very similar to what has recently beensuggested by (Aptina's Clarity+ Solution, 2013). Although this approachmoves away from the standard Bayer pattern, it is however in keepingwith the Color Filter Array (CFA) configuration that is standard for theutilization of demosaicing algorithms and hence can still have ourapproach of a synthetic, reconfigurable Bayer pattern be applicable.With a clear LR sensor integrated, the green image is extractedsubtractively. More importantly, because the clear sensor ispanchromatic, it is able to not only capture a significant component ofthe green channel, but also capture lower lux values and integrate suchvalues at a significantly greater influence, to produce quality HR andSR images under darker lighting conditions.

A block diagram, is presented in FIG. 13 to highlight the extraction ofan SR-based image from a set of LR observations, including that of apanchromatic LR sensor. One or more steps from FIG. 13 may be omitted orreordered in accordance with alternative embodiments of the invention.As is shown in FIG. 13, first at step 1510 a plurality of monochromeimages, generated from data received be each of a plurality of sensorelements in the sensor array of FIG. 12 is aligned, and at step 1520 anordered set at infinity of R, C and B pixel elements is created. A lowresolution G image is then defined from subtraction of the R, C and BPixels in step 1530. This infinity image is then defined as thereference image in step 1540. Demosaicing is then performed on theordered set at infinity in step 1550. The response of the blue and Redpixel level elements are then amplified based upon the C pixel values.Note that the ghosting artifacts will exist on the data. In spite of theartifacts, salient scene information can still be extracted from theordered set, and thus offsets are computed between the monochromaticimages from artifacts in step 1570.

This step is then followed by the process of modifying the ordered setto adapt to the computed offsets in step 1580, and is achieved bysegmentation/disparity decomposition, in which regions in each of themonochrome images are first segmented, and then their disparities arecomputed. Temporal stability analysis as well as other salient featuresextraction is then attempted. Once the disparity that is associated withevery pixel in the scene is known, one can then modify the initialinfinity-based ordered set to produce a new demosaiced ordered set atstep 1590, based on the disparity computation. This new ordered set willthen constitute a final version of the image for that particular frame.The whole process is then attempted again for each frame at step 1595.Temporal stability can also be used to minimize computational demands,i.e. keeping track of only changes in the field of view, per one or moreof the applications incorporated by reference noted above. This ispreferable, since objects move in the field-of-view, and hence, it isimportant to take that aspect into account in an adaptive demosaicingBayer pattern.

Relevance to Super Resolution Techniques

Although the proposed approach defines disparity as per-image,extrapolated patterns of disparity can be achieved from the disparitydecomposition image that was defined earlier. Disparity decompositiongoes beyond row-wise and column-wise decompositions, and can take thepath of any curve that can be defined and traced along the curve's path.This is made possible because once all the decomposition images arecreated, a complete and ordered set of disparity decompositions can beused to extract the depth map. This is first performed by definingrow-wise extracted differences, and then extended to extract intra-rowinformation as well. This is relatively easy to accomplish, so long asthe row-wise disparities are well-defined in the prior step of disparitydecomposition, as described above. In a sense, a three-dimensional mapis generated from the set of LR images, not just a single SR or HRimage. Rather, a set of HR images, most of which are not complete due tovisual occlusions in the field-of-view are instead generated.

Comparison with Existing Super Resolution (SR) Techniques

Although the technique set forth in accordance with the variousembodiments of the present invention is not considered a conventionaltechnique for super resolution, it does produce an image that is ofsignificantly higher resolution than the set of observation images thatare associated with the problem at hand. Image super resolution is adiscipline of image processing that attempts to generate high-quality,high-resolution images from a set of low-resolution and/or low-qualityimages (Nguyen, 2000). Most super resolution techniques employmultiframe super resolution, using temporal information to glean andextract further spatial details. Ultimately, the goal of superresolution is to provide for sub-pixel resolution, relative to thecoordinate system that is associated with the original dataset, from theset of low-resolution observations/images. The approach set forth inaccordance with the various embodiments of the present invention will becontrasted with these prior art super resolution techniques andhighlight the uniqueness of the inventive approach relative to theseexisting super resolution techniques. In (Nguyen, 2000) moreconventional super resolution techniques answer the question “Given aset of M×N observations, and a resolution enhancement factor of r, howdoes one reconstruct an enhanced image rM×rN”.

The problem is formulated as that of interpolating between a set of datathat have been sampled on a theoretical higher-resolution grid. Forinstance, a low resolution frame, f_(k), is given by:f _(k) =DC _(k) E _(k) x+n _(k), 1≦k≦p

where D is the down-sampling operator, C_(k) represents theblurring/averaging operator, E_(k) represent the affine transforms thatmap the HR grid coordinate system to LR. x is the unknown and ideal HRimage, and n_(k) is additive white noise. We note also that (Nguyen,2000):f=Hx+n

where H would be a complete system matrix with dimensions defined aspMNxr²MN. The dimensions of H are directly related to the number of datasamples and unknowns, which is usually a large and computationallycumbersome number. Most approaches of super resolution techniques employvariants to the idea of understanding H, along with what can beextracted and interpolated on a HR grid coordinate system. Thiscomputational complexity in the approaches reflects upon attempts aimedat extracting structure, redundancy, as well as irregularities, amongother salient features, to try and reduce this highly complex probleminto a more manageable problem set. See for example FIG. 14 depictingthree frames of low resolution data, offset from each other on a higherresolution grid.

Multichannel Super Resolution

For reasons that are related to the assumed input LR set to theinventive system, multichannel SR will be discussed briefly as well.Multichannel SR is an area of SR that is often referenced, and employsthe utilization of various light-sensitive frames with lower resolutionimagers, such as low-resolution frames of primary color images that aresubtending the same scene. These lower resolution frames generateobservations that are slightly offset from one another and can be usedto generate a higher resolution image. This is mentioned because one setof inputs to the various approaches in accordance with the presentinvention consists of such low-resolution primary color frames (red,green, blue).

As noted with respect to FIGS. 2(a) and 2(b) and a setup of a micro lensarray, the Bayer pattern that is usually associated with individualpixel elements is replicated on a macro-level. This means that fourlenses are placed on top of an image sensor, with four images beinggenerated.

Image Restoration

A special case of SR is image restoration, in which an ordered linearset is created from the lower resolution observations through regularlysampled data from the LR images. Image restoration strives to “restore”or rather, rearrange the lower resolution pixels onto a fixed pattern ofthe high-resolution coordinate grid. An illustration of imagerestoration is presented in FIG. 15, presenting an ordered set of dataon the high resolution grid. The various embodiments of the presentinvention also differ significantly from image restoration depicted inFIG. 15, as described above.

Application—Manipulating an Image with Front-Facing Camera while Takinga Picture: Pinch and Zoom Functionality

Enabling a smartphone with two forward-facing cameras or a micro lensarray camera to allow the user to control the zoom action of the cameraapplication by using a pinch gesture in a 3D environment; thus allowingfor the user to achieve the appropriate zoom level without having tomove the phone from the current location (i.e., not having to touch thescreen while actively aiming) or obscuring the screen/objects in FOV.See FIG. 16 for an illustration of picture snapping functionality.

Hence, present a method is presented for enabling a smartphone with amicrolens array, or alternatively, two forward-facing cameras to allowthe user to take pictures by using a set of predefined gestures in a 3Denvironment, such as a pinch gesture or a thumbs-up gesture. This wouldallow the user to take faster photos without obscuring the objects inthe field of view. Alternatively, users can change the zoom by movingtheir hand back and forth in the direction of and away from the phone.

Another implementation in accordance with the present invention involvesenabling a smartphone camera with gesture controls to also allow thephone to be used with a tripod so that the user can take self-portraitsfrom a 1 m-3 m distance, so a telescoping tripod attachment to the phonecould be sold as an accessory with the gesture application. Dual sensorscan also be used instead of microlens array sensors, on the back facingcameras and the user can take group portraits by gesturing a thumbs-upto the camera. See FIG. 17 for an illustration.

Controlling a Mobile Device and Enabling Convergence Applications

Another use case involves using the cell phone as a communication devicefor convergence applications in the living room. In such a case, thephone is used as the gestural interface/compute engine. A smartTV isused as the main display/render device for running a game or anotherapplication. Hence, convergence becomes defined as distributing theworkload between the smartphone and the smartTV, in which the smartphoneacts as the main compute device for detecting gesture recognition, andthe smartTV acts as the main compute device for running variousapplications as well as cloning the screen. See FIG. 18 for anillustration.

All applications described can be applied to a phone, tablet or slate,as well as a watch or other mobile computing device (See FIG. 19)

Application—Eye Tracking in Three Dimensions and Face Mapping

Another application involves face mapping. In such an application, eyescan be tracked by a number of lower resolution monochrome sensors. Thesensors are then matched for color and gray value by an algorithm suchas the one defined in the applications noted above and incorporatedherein by reference, with which depth can be extracted. This is thenused to get the pitch and yaw that is associated with the eye movement,as well as temporal tracking. With temporal stability as a feature thatis extracted from the depth analysis that is suggested in theapplications noted above, more degrees of freedom are associated withthe eye movement.

Another variant on this approach identifies the components of the pupilsthat are white and associates these components with monochromaticresponses in multiple monochromatic LR sensors. Matching is thenattempted on the redundant information in a number of the channels, suchthat these redundancies are exploited to further extract features thatcan be used for matching. These include shape as well as temporalstability that has been mentioned above. Given the location of thecamera, information about a mobile device, as well as accurate 3D eyetracking with six degrees of freedom, tracking of a person's gaze can bedone quite accurately by mapping the gaze onto the screen.

Application—Face Mapping

Full face mapping can also be approached in a similar manner to what hasbeen described for eye tracking, i.e., specifically, face tracking isdone by exploiting gray scale redundancies across monochromelower-resolution images of the face. These redundancies, according tothe process that has been described in the applications incorporatedherein by reference, noted above, can then be segmented, disparitydecomposed, matched, and then matched for higher resolution images aswell.

Note that in all of these applications, stereo imaging, which can beconsidered a special form of array imaging can be used to replace thesuggested configuration. So, in all of these applications, it isimportant to note the many similarities between stereo imaging and arrayimage sensors.

Application Mapping the Surrounding Environment

An image sensor array can be mounted on eye glasses, such as Google®glass, but with or without the augmented reality portion. A pedestrianmay point at an object of interest and get information about the object,its location, as well as other information directly previewed on awearable display, such as a smart watch.

Application—Measurement Device

A measuring device is further presented in accordance with analternative embodiment of the invention takes advantage of thethree-dimensional measurement capabilities of the sensor. Specifically,an interactive device may be developed that allows the user to highlighta region in the field of view of the camera. For instance, a coffeetable can be highlighted by the user through the touchscreen on theirphone or tablet, or through pointing or the like as noted above withrespect to the other embodiments of this invention. The coordinates ofthe highlighted region are then preferably extracted from thetouchscreen, as well as the associated segmented region of interest. Theregion may then be further segmented in all the lower resolutioncomponent images, be they monochromatic, saturation-based, or having anyother color or imaging attribute. Measurement features, such as distancefrom sensor, xyz dimensions, and resolution, may then be extracted andused in an app or other program.

Application—3D Stitching and 3D Mosaicing

Once a three-dimensional representation of a scene is extracted, a usercan move around and images with three-dimensional information built intothem can then be stitched together, effectively creating a rendering ofthe surroundings.

Environmental Awareness

All of the different types of feature extraction tools enable a systemto be more environmentally aware. A system that can track all of thesedifferent features can also enable other aspects of environmentalawareness as well. For instance, a system that is used as a measuringtool can also be used to map the environment around them, by combiningimage mosaicing with the tools that have been described above.

The method and apparatus of the invention may be implemented on one ormore computing devices including appropriate image acquisition sensorsas noted in accordance with the application, one or more processors andassociated storage devices, such as one or more known non-transitorystorage media for storing images, computer code and the like. Additionalcomputing elements may be employed on one or more local devices, one ormore cloud computing environments, or both. It is anticipated that oneor more computer programs for implementing the method may be stored tothe non-transitory storage medium and cause a general purpose CPU,processor, GPU or other computing element to perform one or moreelements or steps in accordance with on or more embodiments of thepresent invention.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding descriptions, are efficiently attained and,because certain changes may be made in carrying out the above method andin the construction(s) set forth without departing from the spirit andscope of the invention, it is intended that all matter contained in theabove description and shown in the accompanying drawings shall beinterpreted as illustrative and not in a limiting sense.

It is also to be understood that this description is intended to coverall of the generic and specific features of the invention hereindescribed and all statements of the scope of the invention which, as amatter of language, might be said to fall there between.

What is claimed:
 1. A method for creating an adaptive mosaic pixel-wisevirtual Bayer pattern, comprising the steps of: receiving a plurality ofmonochromatic images from an array of imaging elements; creating areference ordered set at infinity from the plurality of monochromaticimages; running a demosaicing process on the reference ordered set;creating a color image from the demosaiced ordered set; computing one ormore offset artifacts resulting from the demosaicing process at adistance other than infinity; and modifying the ordered set inaccordance with the computed offsets.
 2. The method of claim 1, whereinthe adaptive Bayer pattern is updated by matching row-wise and columnwise disparity values.
 3. The method of claim 1, further comprising thesteps of: realigning the reference image such that objects that are notat infinity are subtended by a modified Bayer pattern for better imagequality; creating a second pattern based upon the modified Bayerpattern; and generating a second demosaiced image in accordance with thesecond pattern.
 4. The method of claim 1, wherein a hand of a user isincluded in the monochromatic images.
 5. The method of claim 4, whereinthe hand of the user is used to control one or more devices.
 6. Themethod of claim 5, wherein the one or more devices comprises a camera.7. The method of claim 6, wherein the hand of the user is positionedwithin a field of view of the camera.
 8. The method of claim 6, whereinthe array of imaging elements is backward facing and the hand of theuser is positioned behind a display of a camera within the field of viewof the array of imaging elements.
 9. The method of claim 8, wherein apinch gesture by the hand of the user adjusts zoom on the display of thecamera without requiring contact with the display of the camera.
 10. Themethod of claim 8, wherein a thumbs up gesture results in the taking ofa picture by the camera.
 11. The method of claim 8, wherein movement ofthe hand of the user towards and away from the display of the cameraadjusts zoom of the camera.
 12. The method of claim 5, wherein the oneor more devices comprise one or more electronic devices.
 13. The methodof claim 12, wherein the one or more electronic devices are controlledby a gestural interface, each gesture being determined based upon one ormore images acquired by the array of imaging elements.
 14. The method ofclaim 12, wherein the one or more electronic devices comprises atelevision.
 15. The method of claim 12, wherein the one or more devicescomprises a game console.
 16. The method of claim 1, wherein the step ofcomputing one or more offset artifacts is performed only on pixels inthe reference image that have changed from a prior image.
 17. The methodof claim 1, further comprising the steps of: highlighting on atouchscreen, by the user, one or more regions in the color image;extracting the coordinates of the highlighted region from one or more ofthe color image and the set of monochromatic images; segmenting theregion in the one of the set of monochromatic images and the color imagefrom which the coordinates were extracted, determining a distance to thehighlighted region on the display; determining one or more dimensions ofthe highlighted region in accordance with the demosaicing process. 18.The method of claim 17, wherein the highlighted region is defined bydetection of an object on the touchscreen.
 19. A system for creating anadaptive mosaic pixel-wise virtual Bayer pattern, comprising: an arrayof imaging elements for acquiring a plurality of monochromatic images;and a processor for creating a reference ordered set at infinity fromthe plurality of monochromatic images, running a demosaicing process onthe reference ordered set, creating a color image from the demosaicedordered set, computing one or more offset artifacts resulting from thedemosaicing process at a distance other than infinity, and modifying theordered set in accordance with the computed offsets.
 20. Anon-transitory storage medium having a computer program stored thereon,the computer program causing a general purpose computer to perform thesteps of: receiving a plurality of monochromatic images from an array ofimaging elements; creating a reference ordered set at infinity from theplurality of monochromatic images; running a demosaicing process on thereference ordered set; creating a color image from the demosaicedordered set; computing one or more offset artifacts resulting from thedemosaicing process at a distance other than infinity; and modifying theordered set in accordance with the computed offsets.
 21. Thenon-transitory storage medium of claim 20, wherein the general purposecomputer further comprises a graphical processing unit.